In many occupations workers are subject to possible blindness or eye damage as a result of exposure to light flashes of great intensity. For example, military flight crews must maintain their ability to function in an environment of nuclear explosions. For their protection, electro-optic shutters based on the properties of transparent ceramics such as lanthanum-modified lead zirconatetitanate (PLZT) have been developed for flight helmet and aircraft cockpit windows. These shutters are essentially a Kerr cell having a transparent ferroelectric ceramic with electrodes deposited so as to selectively polarize the cell. A fixed polarizing lens is mounted in line with the light source, the cell and the viewer. The fixed lens and the cell are usually arranged such that when an appropriate control voltage is supplied to the cell, the polarizations of the cell and the lens are parallel to enable light to pass through the shutter relatively unhindered. However, when the control voltage is removed from the cell, its polarization rotates 90.degree. and no light will pass through both the fixed lens and the cell. As the voltage to the cell is subsequently increased, the polarization of the cell rotates back to its original orientation, and the amount of light passing through the shutter increases. The instant invention relates to the controller which provides the voltage to control polarization of the cell.